Changes in visual function and optical and tear film quality in computer users

Purpose: To assess changes in visual function and optical and tear film quality in computer users. Methods: Forty computer workers and 40 controls were evaluated at the beginning and end of a working day. Symptoms were assessed using the Quality of Vision questionnaire (QoV), 5-item Dry Eye Questionnaire (DEQ--5) and Symptom Assessment in Dry Eye version II (SANDE II). Tear film quality was evaluated using the Medmont E300 dynamic corneal topography tool to measure the tear film surface quality (TFSQ), TFSQ area and auto tear break- -up time (TBUT). Optical quality was assessed by measuring high, low and total ocular aberrations with a Hartmann-Shack wavefront sensor. Visual performance was assessed by measuring photopic and mesopic visual acuity, photopic and mesopic contrast sensitivity and light disturbance. Results: Poorer DEQ-5, QoV and SANDE II scores were obtained in computer workers at the end of the working day compared with controls ( p <= 0.02). Computer workers exhibited a higher (worse) TFSQ and TFSQ area at visit 2 compared with visit 1 ( p <= 0.04), while no significant differences in TBUT (p >= 0.19) or ocular aberrations were observed (p >= 0.09). Additionally, both light disturbance ( p <= 0.04) and mesopic and photopic contrast sensitivity worsened at several spatial frequencies (p <= 0.04) throughout the working day in computer workers, while visual acuity remained unchanged (p >= 0.07). In contrast, control subjects exhibited no decrease in any variable during the day. Conclusions: While visual acuity remained unchanged, several aspects of visual function and quality of vision decreased over a day of computer use. These changes were accompanied by greater dry eye symptoms and tear film changes, which are likely to have played a fundamental role. The present study provides insight into new metrics to assess digital eye strain.